1. Field of the Invention
This invention relates to allenic acid esters and to a process for the preparation thereof and further to a process for preparing .alpha.,.beta.,.gamma.,.delta. -unsaturated carboxylic acid esters by rearranging allenic acid esters.
2. Description of the Prior Art
Allenic acid esters are known and are useful as intermediates in the preparation of various types of perfumes, pharmaceuticals, agricultural compounds and the like. For example, U.S. Pat. No. 3,737,452 discloses allenic esters of the formula: ##STR1## wherein "R" in formula (I) is a primary or secondary lower alkyl of 1 to 6 carbon atoms. These compounds are prepared by reacting 3-methyl-1-butyn-3-ol with an orthoester and may be rearranged to yield the corresponding lower alkyl 5-methylhexa-2,4-dienoate in the presence of a base.